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RFC 2131 / MECHANISMS

Discover and select an address

01

A new client discovers servers, selects an offer, and requests the chosen allocation before using it.

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DIAGRAM§ 3.1 ↗
RFC 2131 · § 3.1EXAMPLE
4 / 4
Discover and select an addressDiscovery, offer, selection, and confirmation appear as distinct ordered messages.clientserverDISCOVEROFFERREQUESTACKcandidateConfirmed; perform final conflict checkIllustrative dynamic allocation; multiple offers are possible
04
Confirm the allocation.

After confirmation, the client performs final conflict checking before use.

Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references
KEY POINT

An offer is not yet permission to use the address.

  • DHCPDISCOVER can reach multiple servers, which may return competing DHCPOFFER messages.
  • The selecting client broadcasts DHCPREQUEST identifying its chosen server and requested address.
  • DHCPACK confirms the configuration; dynamic allocation grants a finite lease.
DETAILS

DHCP also supports automatic permanent allocation and administratively assigned manual allocation. The familiar four-message flow illustrates dynamic allocation.

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Privacy
All chapters in this RFC
  1. Discover and select an address
  2. Reach a server through a relay
  3. Renew before the lease expires
  4. Validate a remembered address
  5. Check conflicts and release addresses
  6. Request settings without a lease
RFC 9700 / CHAPTERS

Chapters

For full details, tables, algorithms, and exceptions, read the original RFC.

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